1-hydroxy-2-naphthamide couplers for color photography



United States Patent Office 3,135,609 Patented June 2, 1964 3,135,609I-HYDROXY-Z-NAPHTHAMIDE CGUPLERS FOR COLUR PHOTOGRAPHY Gnenther H.Klinger, Binghamton, N.Y., assignor to General-Aniline 8: FilmCorporation, New York, N.Y., a corporation of Delaware No Drawing. FiledJune 29, 1960, Ser. No. 39,464 4 Claims; (Cl. 96-100) This inventionrelates to color photography and to compounds which form dyes' oncoupling with a developing agent to produce colored images. Inparticular my invention relates to coupler compounds for forming cyandye images and to photographic emulsions containing such couplers.

It is known to produce colored photographic images wherein a colorformer or coupling component reacts with the oxidation product of aprimary aromatic amino developing agent. In processes of this type thesubtractive method of color formation is ordinarily employed with theresult that the photographic images so obtained are composed of thesubtractive primary colors, i.e., cyan, magenta and yellow. It is thecommon practice to use phenols or naphthols for producing cyan imagesand pyrazolones for magenta images, whereas open chain reactiveketomethylene compounds serve as a source of the yellow dye images.

The present invention is concerned with naphthol couplers andwith cyanimages produced on color development therefrom.

In a multilayer color photographic element the red sensitive layercontains a color former which on color development produces a cyan dyeimage. Since the function of the cyan dye image is to filter or regulatethe amount of the red absorption in a color transparency or print, it isobvious that the cyan image should not absorb significantly in the blueand green portions of the spectrum. Ideally, a cyan dye should have aspectral absorption which lies at 660-670 m with virtually no absorptionin the blue and the green.

There have been numerous proposals of coupler structures which on colordevelopment yield cyan dye images approximating the aforedescribedspectral characteristics. For instance, cyan dye forming couplers areknown which are derivatives of l-hydroxy-Z-naphthamide in which thehydrogen atoms on the amide linkage have been replaced by a wide varietyof substituents. For example, an aryll-hydroxy-Z-naphthamide coupleryields on color development a dye that absorbs around 690 me and istherefore too far in the red portion of the spectrum. The alkylnaphthanilides on the other hand fall short of the desired spectralabsorption and the structures form dyes, the absorption of which usuallyfalls within the range of 630-640 Ill 1.. Mixed substituents of alkyland aryl groups have likewise been prepared, but these couplers giverise to dye images absorbing too much light in the shorter Wave lengths.

Aside from their spectral properties, dyes composing photographic imagesmust also possess other properties peculiar to the photographic art.Thus, it is essential that photographic dye images endure varyingconditions of light, heat and humidity and the couplers themselves mustpossess stability and not give rise to various stains or discolorationof the final prints or transparencies. It can thus be seen that a colorcoupler and the dyes produced therefrom must be possessed of certainspecific properties before they are'suitable for use in colorphotography.

It is, therefore, a primary object of this invention to provide novelphotographic coupler compounds capable of producing cyan dye images oncolor development.

It is a further object of this invention to provide coupler compoundswhich produce cyan dye images characterized by a high degree of redabsorption while simultaneously displaying little or no absorption inthe blue or green portions of the spectrum. It is a still further objectto provide coupler compounds which produce dyes having a high degree ofresistance to light, heat and excessive humidity.

Other objects will appear as the description proceeds.

The aforesaid objects are accomplished according to my invention by theuse of certain l-hydroxy-Z-naphthamide coupler compounds containing inthe amide portion thereof a long aliphatic chain for rendering thecouplers non-difi'using in photographic emulsions.

Couplers of this type can be depicted by the following general formula:

(I) OH wherein n is an even integer such as 2, 4, 6 etc. and Rrepresents a non-diffusing aliphatic group of from 8 to 20 carbon atomsand X represents hydrogen or a solubilizing or salt forming group suchas a sulfo radical, a carboxylic acid radical etc.

Couplers falling within the ambit of the above general formula can befurther divided into two sub-generic structural types: (1) hydrophiliccouplers characterized by the presence of a solubilizing group; and (2)lipophilic couplers soluble in oily solvents. These sub-genericstructures can be represented by the following two general formulas:

(II) (DH wherein n has the values given above. It is to be unnc. stoodthat Formula III also includes the ammonium and alkali salts thereof. a

Couplers falling within the ambit of the formula include the followingstructures:

In general I prepare my novel cyan color formers by reacting1-hydroxy-2-phenylnaphthoate with an alkylene diamine in a 1:1 moleratio whereby is produced an N-aminoalkyl l-hydroxy-Z-naphthamide. Thislatter intermediate is then reacted with a higher alkanoic acid or acidhalide thereof in order to acylate the amino group of the N-aminoalkyll-hydroxy-Z-naphthamide with concomitant production of anaphthol-2-naphthamide coupler containing a non-diffusing chain attachedto the terminal amino group.

In the event it is desired to produce a hydrophilic type coupler, thenthe intermediate N-aminoalkyl naphthamide is reacted with an a-sulfohigher alkanoic acid of from to carbon atoms employing, for instance,the wellknown phosphazo reaction. If, on the other hand, it is desiredto obtain a lipophilic color former, then the N-aminoalkyl1-hydroxy-2-naphthamide is reacted with the unsubstituted higher chainalkanoic acid or the acid chloride thereof.

Suitable higher carboxylic acid derivatives which I have found suitablefor practicing the invention include the following: caprylic acid,pelargonic acid, capric acid, undecylic acid, lauric acid, tridecanoicacid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid,stearic acid and the like.

In the event that it is desired to use the a-SUlfO alkanoic acid theseentities are well-known in the chemical art and are, furthermore,commercially available. In general their preparation involves reactingthe alkanoic acid with sulfur trioxide in a suitable solvent wherebyintroduction of the a-sulfo group is effected. a-Sulfocarboxylic acidsare bi-functional acids and can react to give mono or dialkyl salts,ester amides or combinations of the reaction products. The oc-SlllfOalkanoic acids contain a strongly ionized sulfonic acid group incombination with a comparatively weakly ionized carboxylic group. Saltformation, for example, will occur first and completely at the strongersulfonic acid group leaving a free carboxylic acid group if so desired.For further information on these chemical intermediates, reference ismade to Technical Bulletin G-7Rl, March 20, 1957, and published by theArmour Industrial Chemical Company, Division of Armour & Company, 110North Wacker Drive, Chicago 6, Illinois.

The alkylene diamines, which are reacted with l-hydroxy-2-phenylnaphtlroate to produce the requisite N- aminoalkyll-hydroxy-Z-naphthamide intermediates, are also well-known chemicalentities and are fully described in the technical literature.Alkylenediamines which we have found suitable for practicing theinvention include ethylenediamine, tetramethylenediamine,hexamethylenediamine and the like.

The following are illustrative of the preparation of the couplersdescribed herein, but such examples are not to be taken as limiting orin any way restricting the invention.

Example I Compound 2 was prepared in the following manner.

(1) g. (0.5 mole) ethylenediamine l hydroxy 2- naphthamide (IntermediateI),

(2) 202.5 g. (0.5 mole) a-sulfostearic acid,

(3) 400 ml. dry pyridine,

and (4) 800 ml. benzene were charged into a round bottom 3-necked 5liter flask. The flask was equipped with a dropping funnel, a stirrerand a water trap (Dean-Stark type) and a condenser with a drying tube.The mixture was refluxed (electric heating mantle) until all traces ofmoisture were removed. This required about 2 hours. Rapid stirring wasused to prevent excessive foaming. The mixture was cooled to about 5 C.in an ice water bath and a solution of 55 ml. of PCl in 100 ml. of drybenzene was added dropwise over a period of about 30 minutes. Themixture was stirred rapidly during the addition and stirring wascontinued for 2 hours at room temperature, followed by refluxing on asteam bath for 2 /2 hours.

A solution of 80 g. of sodium carbonate monohydrate and g. of sodiumacetate (anhydrous) in 500 ml. of water was added and the mixturerefluxed for 5 minutes. After cooling to 3035 C., the mixture wastransferred to a separatory funnel and the organic phase separated. Twohundred ml. of benzene were added and the layer was washed 3 times withsaturated salt solution. The solvent was removed by distillation atnormal pressure until the distillate was free of water, then bydistillation at reduced pressure (l-2 mm.) until all the benzene andpyridine were removed. The residue was crystallized from propanol (6 ml.per 1 g. of residue) and treated with decolorizing charcoal (5% byweight). The yield after two recrystallizations:-180 g. The material wasdried at reduced pressure (l-S mm. Hg). For further purification (toinsure the removal of photo-active impurities) it was dissolved in 80%acetic acid, (2 ml. of 80% acetic acid per 1 g. of color former) cooledand precipitated with 6 N.HCl (4 ml. per 1 g. of color former). Theaqueous layers were decanted and the syrup transferred to a round bottomflask. To the syrup were added a 10 fold amount of benzene, based onamount of color former, and all the water was removed by azeotropicdistillation. The benzene was removed by distillation under reducedpressure. The dry residue was dissolved in the 6 fold amount ofnpropanol, filtered and the filtrate distilled to dryness. The residuewas finally dried on a steam bath at 0.1 mm. Hg and then powdered. Yield120-435 g.

The N-aminoethyl-l-hydroxy-Z-naphthoate used in the above describedpreparation was obtained as follows:

(a) g. (3 mole) of ethylenediamine (98%) (b) 264 g. (1 mole) ofphenyl-1-hydroxy-2-naphthoate (c) 2000 ml. benzene (a) and 1000 ml. ofbenzene were charged into a 5 liter 3-necked flask equipped with adropping funnel, stirrer, condenser and thermometer. The amine-benzenemixture was heated to 50 C. on a steam bath and a solution of (b)phenyl-l-hydroxy-Z-naphthoate in (c) was added slowly (temperaturemaintained at 50 C.). After the addition was completed, the temperaturewas kept at 50 C.

for 1 hour and then refluxed for 1 hour. On cooling, the solid wasfiltered, washed and crystallized from propanol using ether as the finalwashsolvent. Yield=135 g.; M.P. 161163 C.

Example II Using the procedure as given above for Example I, compound 6was prepared excepting that u-sulfopalmitic acid was substituted fora-sulfostearic acid.

As disclosed elsewhere the color-forming components described herein areof the non-diifusing variety, that is, they are designed to beincorporated directly in the silver halide emulsion. The methodsemployed for combining color couplers in a photographic emulsion areknown and described in the prior art and such methods are applicable tothe couplers of the present invention. In the event that color-formingcomponents include a solubilizing group as represented by a sulfosubstituent, such entities can be used in the form of their solublesalts as, for example, their alkali metal salts which are miscible Withaqueous solutions of colloids of the type commonly employed as carriersfor silver halide emulsions. As previously pointed out, the couplersdescribed herein may be of the lipophilic or hydrophobic variety. In thelatter instance, the couplers are advantageously dissolved in a highboiling organic water immiscible oily solvent and the resulting solutiondispersed or homogenized in the silver halide emulsion. For instance, asolution of 1.5 g. of the coupler is dissolved in 6.0 g. of a mixtureconsisting of 50 parts of phenyl alcohol, 40 parts of tricresylphosphate and 10 parts of n-butylphthalate, and the resulting solutiondispersed in 20 milliliters of 6% gelatin solution containing 0.05 ml.of lauryl sulfate as a surfactant. Emulsification is efiected by highspeed agitation in a small Waring Blendor.

The coupler dispersion is then mixed with 50 g. of a melted silverhalide gelatin emulsion and then coated on a suitable support, set anddried in the usual manner. On exposure and development of the coatingswith a primary aromatic amino developing agent and subsequent removal ofthe silver image, a brillant cyan dye image is obtained, the principalabsorption being in the highly desired 660- 670 mp. of the visiblespectrum While simultaneously showing little or none of the undesirableabsorption in the green portion of the spectrum.

Various photographic developing agents can be employed with the couplersof my invention. The primary aromatic amino developing agents aregenerally suitable including the phenylenediamines and aminophenols.Suitable compounds are 4-aminoaniline, 4-ethylaminoaniline,4-dialkylaminoaniline, e.g., 4-dimethyl-aminoaniline,4-diethylaminoaniline, 4-[N-(B-hydroxyethyl)-N-ethyl] amino aniline,4-amino-N-ethyl-N-(B methanesulfonamidoethyl)-2-methylaniline sulfate,and the like. The above developing agents are preferably used in theform of their salts such as the hydrochloride or hydrosulfate as theyare more soluble and stable than the three bases. All of these compoundshave a primary amino group which enables the oxidation product of thedeveloper to couple with the color compounds to form dye images. Afterremoval of the silver image by bleaching and fixing in a mannerwellknown to the art, the color image remains in the emulsion.

A suitable developing solution can be prepared as follows:

G. 2-amino-S-diethylaminotoluene 2 Sodium carbonate (anhydrous) 20Sodium sulfite (anhydrous) 2 Potassium bromide 0.2

Water to make 1 liter.

The exposed silver-halide emulsions containing the color formers aredeveloped in the above solution in the usual manner.

The photographic dye images produced from my couplers can be containedin the usual colloidal carriers such as layersof gelatin or similarwater permeable carriers and in this connection mention is made ofalbumen, organic esters of cellulose, polyvinyl alcohol, carboxyl methylcellulose, starch, casein and the like. The carrier may be supported bya transparent medium such as glass, a cellulose ester or syntheticresin, or a non-transparent reflecting medium as represented by paper oranopaque cellulose ester containing suspended pigment. The emulsion maybe coated as a single layer on a support or as one of a number ofsuperimposed layers, or one of both sides of the support. The variouslayers may be differently sensitized to specific portions of theelectromagnetic spectrum by the use of optical sensitizing dyes such asthe well known cyanine dyes. The sensitization of silverhalide emulsionsis described in detail in the photographic literature.

As above pointed out, the coupler structures of the type describedherein yield on color development cyan dye images having their principalabsorption between 660-670 m while exhibiting very little absorptionbelow 560 me. These spectral properties are extremely valuable anduseful in color photography.

It will be understood that the examples and modifications set forthherein are illustrative only and my invention is to be taken as limitedonly by the scope of the appended claims.

I claim:

1. A light sensitive silver halide photographic emulsion containing acoupler selected from the class represented by those of the followingformulae:

H H e C ONH(CH2) n NC 0- R wherein R is an alkyl group of from 8 to 20carbon atoms, n is an even integer ranging from 2 to 6, and X isselected from the class consisting of hydrogen, ammonium and alkalimetal.

2. A light sensitive silver halide photographic emulsion containing acoupler represented by the following formula:

wherein R is an alkyl group of from 8 to 20 carbon atoms, n is an eveninteger ranging from 2 to 6, and X is selected from the class consistingof hydrogen, ammonium and alkali metal.

3. A light sensitive silver halide photographic emulsion containing acoupler represented by the following formula:

4. A light-sensitive silver halide photographic emulsion containing acoupler of the following formula:

References Cited in the file of this patent UNITED STATES PATENTSSalminen et a1 Nov. 16, 1954 Salminen et a1 June 14, 1955 Popeck et a1Apr. 8, 1958 Whitmore Aug. 19, 1958 Roth et a1. Mar. 5, 1963 FOREIGNPATENTS France Nov. 13, 1957

1. A LIGHT SENSITIVE SILVER HALIDE PHOTOGRAPHIC EMULSION CONTAINING ACOUPLER SELECTED FROM THE CLASS REPRESENTED BY THOSE OF THE FOLLOWINGFORMULAE: